Objective: To determine the computed tomographic imaging features predictive of adnexal malignancy and evaluate the accuracy of contrast-enhanced helical computed tomography (CT) in the characterization of adnexal masses.
Materials and Methods: The institutional review board waived the informed consent requirement for this retrospective study, which was Health Insurance Portability and Accountability Act compliant. For 143 consecutive patients who underwent preoperative contrast-enhanced CT of the abdomen and pelvis and had adnexal masses found at surgical pathology, preoperative contrast-enhanced computed tomographic scans were retrospectively and independently reviewed by 2 radiologists. Receiver operating characteristic analysis was used to assess the value of contrast-enhanced CT in detecting and characterizing adnexal masses. Feature analysis was performed to select the findings with the highest sensitivities and specificities for predicting malignant lesions. Interobserver variability was assessed using κ statistics.
Results: At surgical pathology, 234 adnexal masses were found (165 were malignant). Readers 1 and 2 detected 215 and 216 (92%) adnexal masses, respectively. For both readers, the features most predictive of malignancy were heterogeneity for a solid lesion, multilocularity (>3 locules), irregular and thickened cystic septations or walls, and the presence of internal vegetations for a cystic lesion. Irregular lesion contour and ancillary findings, including ascites, peritoneal implants, lymphadenopathy, and pleural effusion, were predictive of malignancy in both solid and cystic lesions. In diagnosing malignancy in all patients and in the subgroup without ancillary findings, areas under the receiver operating characteristic curves were 0.88 (95% confidence interval [CI], 0.84-0.93) and 0.89 (95% CI, 0.83-0.96) for reader 1, respectively, and 0.90 (95% CI, 0.86-0.94) and 0.88 (95% CI, 0.80-0.97) for reader 2, respectively. Interobserver agreement (κ = 0.71) was good.
Conclusions: Contrast-enhanced helical CT is highly accurate in characterizing adnexal masses as malignant. Recognition of the computed tomographic features most often associated with adnexal malignancy will assist in more confident use of this modality and may potentially obviate the need for additional imaging studies before treatment selection.